The present invention relates to diagnosing and saving power to a physical storage device in a storage system.
A storage system comprising a plurality of physical storage devices is known. This type of storage system, for example, includes a disk array apparatus comprising a plurality of disk devices (for example, hard disk drives) in an array. As technology related to diagnosing and saving power in a disk array apparatus, for example, there is the technology disclosed in Japanese Patent Laid-open No. 2000-293314, which is referred to here as Literature 1. According to Literature 1, a disk array apparatus controls the power saving of a disk device (selects power ON/OFF or a power-saving mode) subsequent to the passage of a predetermined period of time during which there has not been an access from an upper-level device. Further, when there is an access from an upper-level device, if the power to the access destination disk device is OFF, the disk array apparatus executes the access subsequent to turning ON the power to this disk device. Further, the disk array apparatus also performs diagnostics on the respective disk devices.
If the power to a disk device is turned OFF and left OFF, the power consumed by this disk device can continue to be conserved. However, even if the power remains OFF, a disk device can still malfunction due to aging and the like. If power to a disk device is turned ON and data is stored in this disk device without noticing the effects of aging, there is the danger of this data being lost due to the malfunctioning of this disk device. This kind of problem is not limited to a disk device, and is also possible in other types of physical storage devices.